Fluvoxamine augmentation in risperidone-resistant schizophrenia: an open trial

The clinical potentials of adjunctive fluvoxamine to clozapine treatment: a systematic review

RATIONALE

New clozapine optimization strategies are warranted, as some patients do not achieve sufficient response and experience various adverse effects. Fluvoxamine is a potent CYP1A2 inhibitor and may increase the ratio of clozapine to its primary metabolite N-desmethylclozapine (NDMC).

OBJECTIVES

This study aims to review all pharmacodynamic effects and the adverse effect profile of changing the clozapine/NDMC ratio with adjunctive fluvoxamine.

METHODS

MEDLINE, Embase, and the Cochrane Library were searched with the search terms "clozapine" and "fluvoxamine" without any time limit. Language was restricted to English, Scandinavian, Polish, and German. Studies were sorted for relevance based on title and abstract. Clinical recommendations of potential indications/effects were graded as level A, B, C, or D depending on studies of high, moderate, low, or very low quality, respectively.

RESULTS

Based on data from 24 case reports/series, seven cohort studies, and two randomized controlled trials, 241 patients were studied. Evidence (A) supported that adjunctive fluvoxamine increased clozapine plasma levels. This may increase the probability of response in patients, where sufficient clozapine plasma levels cannot be achieved. Adjunctive fluvoxamine reduced metabolic adverse effects of clozapine (B) but not agranulocytosis risk (B). Although depressive or obsessive-compulsive symptoms may improve, a SSRI with no CYP1A2 inhibition should rather be used (C). No studies investigated the effect of adjunctive fluvoxamine to minimize clozapine rebound psychosis (D) or to reduce the effects of smoking on clozapine plasma levels (D).

CONCLUSIONS

Adjunctive fluvoxamine may have clinical potentials for optimizing clozapine treatment but further clinical studies are warranted to explore the clinical implications.

Clinical utility of the risperidone formulations in the management of schizophrenia

Risperidone is one of the early second-generation antipsychotics that came into the limelight in the early 1990s. Both the oral and long-acting injectable formulations have been subject to numerous studies to assess their safety, efficacy, and tolerability. Risperidone is currently one of the most widely prescribed antipsychotic medications, used for both acute and long-term maintenance in schizophrenia. Risperidone has better efficacy in the treatment of psychotic symptoms than placebo and possibly many first-generation antipsychotics. Risperidone fares better than placebo and first-generation antipsychotics in the treatment of negative symptoms. Risperidone's long acting injectable preparation has been well tolerated and is often useful in patients with medication nonadherence. Risperidone has a higher risk of hyperprolactinemia comparable to first-generation antipsychotics (FGAs) but fares better than many second-generation antipsychotics with regards to metabolic side effects. In this article, we briefly review the recent literature exploring the role of risperidone formulations in schizophrenia, discuss clinical usage, and highlight the controversies and challenges associated with its use.

Escitalopram in the treatment of negative symptoms in patients with chronic schizophrenia: a randomized double-blind placebo-controlled trial

Antidepressant medication treatment has been associated with improvement in negative symptoms in patients with schizophrenia. In this study, we evaluated the efficacy of escitalopram for the treatment of negative symptoms in patients with schizophrenia. Under double-blind conditions, 40 patients with chronic schizophrenia were randomized to add-on treatment with escitalopram (up to 20mg) or placebo for 10weeks. The primary outcome measures were the scores on the Positive and Negative Syndrome Scale (PANSS)-negative subscale and the Social Functioning Scale (SFS). Secondary outcome measures included the Positive and Negative Syndrome Scale (PANSS)-total and positive scales, the Scale for Assessment of Negative Symptoms (SANS), the Clinical Global Impression Scale (CGI), the Hamilton Depression Rating Scale (HDRS) and the Abnormal Involuntary Movement Scale (AIMS). Of 40 patients, 36 completed the study and another 2 were excluded after 8weeks due to side effects. Thus, 38 patients (19 on both treatment arms) were considered in the efficacy analysis. The reduction in the PANSS negative subscale score was 5% for escitalopram and 10% for placebo (NS). There were no significant inter-group differences in primary and secondary endpoints. Escitalopram was well tolerated, but was not more effective than placebo in the treatment of negative symptoms in patients with chronic schizophrenia. Further work in this field is needed to determine whether some subgroups of patients with negative symptoms may nevertheless respond to antidepressant medications.

Selective serotonin re-uptake inhibitor augmentation in the treatment of negative symptoms of schizophrenia

Negative symptoms are core features of schizophrenia that respond poorly to first-generation antipsychotics and present a major obstacle in rehabilitation. Patients may be somewhat more responsive to clozapine and second-generation antipsychotics but even then, considerable impairment remains. This paper reviews the use of selective serotonin re-uptake inhibitor (SSRI) augmentation of antipsychotics in the treatment of negative symptoms in schizophrenia. Important methodological issues particular to the study of negative symptoms are also discussed. Current evidence indicates that at least two SSRIs, fluvoxamine and fluoxetine, can ameliorate primary negative symptoms in chronic schizophrenic patients treated with first-generation antipsychotics. Onset of improvement may be detected within 2 weeks of starting treatment. The combination is well-tolerated, although as antipsychotic drug concentrations may rise, close monitoring of drug doses and possibly drug concentrations is needed. So far, evidence regarding SSRI augmentation of second-generation antipsychotics is limited and in view of the increasing use of these newer agents, controlled studies are urgently needed. SSRI augmentation may be a useful addition to the treatment of schizophrenic patients with persistent negative symptoms. The paradoxical findings that both clozapine, a serotonin antagonist, and an SSRI antidepressant added to antipsychotics, can improve negative symptoms suggests that these pharmacologically distinct treatments may share common final mechanisms. A better understanding of these mechanisms can shed light on the pathogenesis of negative symptoms and provide new targets for drug development.

Selective serotonin reuptake inhibitor augmentation in the treatment of negative symptoms of schizophrenia

The treatment of negative symptoms of schizophrenia presents a major clinical challenge. This review examines the evidence pertaining to the efficacy, tolerability and safety of adding selective serotonin reuptake inhibitors (SSRIs) to antipsychotic agents in the treatment of negative symptoms in schizophrenia. Important methodological issues such as differentiating primary and secondary negative symptoms are discussed. The balance of available evidence indicates that at least some SSRIs, fluvoxamine and fluoxetine, can ameliorate primary negative symptoms in chronic schizophrenia patients who are treated with typical antipsychotics. The combination is safe and well tolerated although, as antipsychotic drug concentrations may be elevated, attention to dose and drug monitoring should be considered as appropriate. The effect of SSRI augmentation of atypical antipsychotics requires further study. Combination with clozapine may require particular caution because of potential toxicity if serum clozapine levels rise steeply. SSRI augmentation may be a useful addition to the treatment of schizophrenia.